AI Goals

AI Goals

How PlayerMob's brain is wired, the one pattern worth copying, and an honest note on what is — and isn't — an extension point.

All goals live in games.brennan.playermob.entity.goal and are registered in PlayerMobEntity.registerGoals().

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Goal selector (what the mob does)

Lower priority number = evaluated first / preempts.

Pri	Goal	Role
0	FloatGoal	Swim / don't drown.
1	FleeFromCategoryGoal	Shy: flee + hide near cover.
1	SkepticalWatchGoal	Skeptical: stop & stare; ready weapon/shield if approached.
1	FriendlyGreetGoal	Friendly: approach, crouch-greet, gift.
1	PlayerMobDoorGoal	Open (and, if tidy, close) wooden doors on the path.
2	WeaponAwareAttackGoal	Combat — crossbow / bow / melee (see below).
3	EatFoodGoal	Eat from the backpack when hurt.
3	RaidContainersGoal	Loot chests / barrels / shulkers.
3	RaidArmorStandsGoal	Swap upgrades off armor stands.
3	CollectFloorItemsGoal	Pick up wanted ground items.
6	HarvestCropsGoal	Low-priority forage: harvest ripe carrots/potatoes/beetroot.
8	WaterAvoidingRandomStrollGoal	Idle wander.
9	LookAtPlayerGoal	Idle look.
10	RandomLookAroundGoal	Idle look.

The three personality social goals (pri 1) self-gate on the live disposition — they only run when the mob actually feels that way about a nearby entity, and Skeptical/Friendly also yield when a combat target exists. Flipping a disposition at runtime (e.g. via provocation) instantly changes which one fires; nothing is re-registered.

Target selector (who the mob attacks)

Pri	Goal	Role
1	HurtByTargetGoal	Retaliate against attackers.
2	NearestAttackableTargetGoal	Acquire anything the mob is Aggressive toward (and, if on a train, on the same train).
3	HuntForFoodGoal	Hunt food animals only while hungry — below hostile targeting, so defending beats chasing a cow.

The priority-2 acquisition predicate is:

candidate -> personalityToward(candidate) == Personality.AGGRESSIVE
          && TrainConfinement.allowsTarget(this, candidate)

TrainConfinement is a no-op unless an optional train mod is installed — see Soft-Dependency Integrations. A central sweep in customServerAiStep also drops a target that wanders off the train.

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The pattern worth copying: WeaponAwareAttackGoal

PlayerMob fights with whatever is in its main hand, switching weapons mid-combat. Rather than register three vanilla attack goals at different priorities (their canUse() predicates don't know about "am I holding the right weapon?", so they'd thrash the selector), it composes them inside one outer Goal:

• The outer goal claims MOVE, LOOK, JUMP once, so the selector sees a single stable combat occupant.
• Each tick it picks a delegate by inspecting the main hand — RangedCrossbowAttackGoal, RangedBowAttackGoal, or MeleeAttackGoal.
• Before (re)selecting it calls equipBestWeaponForTarget(target) (ranged when far, melee when close); on a weapon change it cleanly stop()s the old delegate and start()s the new one; on stop() it reverts to the best melee.

This composite-delegate shape is the reusable lesson: when several vanilla goals are mutually exclusive on a condition the selector can't see, wrap them in one goal that owns the flags and routes per-tick. Source.

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Extending the behaviour

Be aware of what's actually open:

• registerGoals() is not an extension point. It's a protected override with no registry or event hook. You cannot add a goal to PlayerMob from another mod without either a Mixin (the config at playermob.mixins.json is wired and empty — drop one into games.brennan.playermob.mixin) or a subclass of PlayerMobEntity registered as your own entity type.
• The reusable, dependency-free bits are the policy classes (ItemPickupPolicy, EquipmentEvaluator, ForagePolicy) and the composite-goal pattern above — see Entity API Reference. If you're building your own mob, copy those; they're stateless and unit-tested.
• Want a real extension hook (e.g. a goal-registration event, or a setPersonality setter)? That's a reasonable contribution — open an issue on the tracker.

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Goal catalogue

Goal	One-liner
WeaponAwareAttackGoal	Composite crossbow/bow/melee combat.
FleeFromCategoryGoal	Shy: flee & hide.
SkepticalWatchGoal	Skeptical: stop, stare, ready defence.
FriendlyGreetGoal	Friendly: approach, crouch, gift.
PlayerMobDoorGoal	Open/close wooden doors.
EatFoodGoal	Eat backpack food when hurt.
RaidContainersGoal	Loot chests/barrels/shulkers.
RaidArmorStandsGoal	Take upgrades off armor stands.
CollectFloorItemsGoal	Pick up wanted ground items.
HarvestCropsGoal	Harvest ripe food crops when idle.
HuntForFoodGoal	Target goal: hunt food animals while hungry.